The osteology of Cromeria nilotica and Galaxias attenuatus. 61 
In Galazias the ribs and epipleurals are similarly distributed ; 
but nearly all the former articulate with parapophyses, and the latter 
are attached to the vertebral bodies instead of to the ribs. 
Many of the peculiarities of the cranium of Cromeria are due 
mainly to the enormous size of the brain. This projects dorsally and 
separates the frontals widely from one another (Fig. D). These bones 
therefore do not take any part in the roofing over of the cranial 
cavity, but, on account of their large size, they occupy nearly half of 
its side wall (Figs. B and F). Those otic bones which are usually seen 
in the dorsal aspect are likewise shifted to the sides. Apart from 
this their relationships to one another are quite normal. The opisth- 
otic is absent. Side by side with the complete enclosure of the foramen 
for the fifth nerve by the prootic (Fig. F 0. pr) goes the largely devel- 
oped alisphenoid (Fig. B as). In the occipital arch all elements are 
present and both supra- and basioceipital take part in the formation 
of the foramen magnum. 
Fig. D. Dorsal view of the cranium of Cromeria. 25: 1. 
Fig. E. The same, of Galaxias. 3: 1. 
e.m mesethmoid, e.p.b‘ dermo-parethmoid, oc.b basioccipital, pa palatine, vo vomer. 
The other letters are the same as in previous figures. 
One small membrane bone (Figs. B and F par) in this region is 
difficult to homologise. It may be regarded as the parietal, or as the 
squamosal. For several reasons the former seems to be the more 
correct view. The supraoccipital (Fig. D oc.s) is so large that one natur- 
ally expects to find the parietals widely separated. In other Teleosts 
the membranous squamosal is very frequently absent; this cannot be 
